Surface effect ship improvements

ABSTRACT

Presented is an improved Surface Effect Ship (SES) that offers the high efficiencies of the pressurized air cushion supported generic flexible bow and stern seal SES but without the generic SES&#39;s shortcomings that are due largely to its 80 percent total hull width flexible bow and stern seals. This is accomplished in the instant invention by use of forward extending rigid bow members positioned both sides of a pressurized hull supporting gas cushion where the width of the sidehulls make up a majority of the width of the instant invention improved surface effect ship with the remainder, less than 35 percent of vessel width normally, made up by a gas cushion forward seal member disposed between the bow members. Gas cushions may extend forward into undersides of the sidehull bow members to further reduce wetted area resistance. Longitudinally oriented fluid fences may be incorporated to at least partially separate portions of the gas cushion and thereby dampen pressure perturbations in the gas cushion(s). A third bow member may be utilized between port and starboard sidehulls.

CROSS REFERENCE TO OTHER APPLICATIONS

[0001] This application is a continuation-in-part to Applicant's earlierfiled applicaiton Ser. No. 10/274654 filed Oct. 21, 2002.

BACKGROUND OF THE INVENTION

[0002] Marine Surface Effect Ships (SES) in their generic form have aupper hull that is rather flat on its underside with downward extendingasymmetrical catamaran sidehull portions either side. These asymmetricalsidehull portions are connected transversely fore and aft by flexibleseals. The boundary of the space thus formed is pressurized with airsupplied by powered blowers to thereby form a deep air layer between thehull and the water's surface. This results in a vessel that has littlewater contact and is therefore quite efficient at high speeds in calmwater.

[0003] Major shortcomings of the generic SES are that: 1) The wide barndoor effect of the flexible bow seal contributes to a drastic increasein resistance and poor sea keeping characteristics when moderate to highseas are encountered, 2) The flexible bow seal allows waves to enter andupset the stability of the supporting gas cushion that is really a hugegas spring. This results in a very uncomfortable 2-4 cycle per secondoscillation that is commonly known as the SES “cobblestone” ride effect,and 3) The large full span flexible bow and stern seals are ratherexpensive and high maintenance.

[0004] Applicant has successfully addressed the shortcomings of thegeneric SES with his patented SEACOASTER Surface Effect CATamaran(SECAT) inventions. SEACOASTER has fine entry bows on long and slendersidehulls with gas cushion recesses built into their undersides. Blowerpressurized air is supplied to the two recesses thereby essentiallyforming two parallel surface effect ships mounted to a common hullstructure. The shortcomings of the generic SES are avoided since thereare no high cost and maintenance flexible seals and there is no gascushion between the sidehulls. The fine entry bows of the SEACOASTER'ssidehulls provide an excellent ride in rough seas and there is no“cobblestone” ride as is experienced with the generic SES.

[0005] However, compared to a generic SES of similar size, theSEACOASTER inventive hull has two shortcomings: 1) It has about 30percent less air cushion surface area and hence requires a highercushion pressure due to the non-pressurized area between its sidehullsand 2) It has more wetted area since it has four sidewalls, one on eachside of each of its air cushions, while the generic SES has only twosidewalls. Even with these relatively minor shortcomings, the SEACOASTERis proving to be a very successful concept.

[0006] The instant invention proposed herein addresses the minorshortcomings of the SEACOASTER concept while still designing out themajor shortcomings of the generic SES. This will be understood uponreview of the following sections.

SUMMARY OF THE INVENTION

[0007] The primary object of the instant invention is to provide a veryefficient and sea kindly marine surface effect ship that is partiallysupported by artificially pressurized gas cushion(s).

[0008] It is a further object of the invention that it include port andstarboard sidehulls and bow members.

[0009] It is related object of the invention that a gas cushion forwardseal member(s) be disposed in a general transverse direction to therebyform a portion of a gas seal for the artificially pressurized gascushion(s).

[0010] It is a directly related object of the invention that the gascushion forward seal member(s) extend at least a majority of thedistance between inboard portions of the port and starboard bow members.

[0011] It is a directly related object of the invention that the gascushion forward seal member(s), as seen in a vertical transverse planeof the improved surface effect ship, are angled to horizontal over amajority of their width.

[0012] It is a further related object of the invention that a gascushion forward seal member(s), as seen in a vertical transverse planeof the improved surface effect ship, be at least in part of aninverted-V shape.

[0013] It is another object of the invention that a powered blowerdischarge into a gas cushion be located proximal an aft end of the gascushion forward seal member(s).

[0014] It is yet another object of the invention that a powered blowerdischarge be accelerated so that the dynamic gas pressure is proximal toor higher than the pressure in the gas cushion before discharge into thegas cushion.

[0015] It is another object of the invention that water contactingportions of the port and starboard bow members extend, as seen when theimproved surface effect ship is moving forward at high speed in a calmsea at a bow up trim angle of one and one-half degrees, forward of anaverage of longitudinal positions, as seen in longitudinal verticalplanes of the improved surface effect ship, of forward water contactingportions of a gas cushion forward seal member by at least ten percent ofa waterline length of the improved surface effect ship.

[0016] A directly related object of the invention is that watercontacting portions of said port and starboard bow members extend, asseen when the improved surface effect ship is moving forward at highspeed in a calm sea at a bow up trim angle of one and one-half degrees,forward of an average of longitudinal positions, as seen in longitudinalvertical planes of the enhanced surface effect ship, of forward watercontacting portions of a gas cushion forward seal member by at leastfifteen percent of a waterline length of the improved surface effectship.

[0017] A further related object of the invention is that the port andstarboard bow members extend, as seen when the improved surface effectship is moving forward at high speed in a calm sea at a bow up trimangle of one and one-half degrees, forward of an average of longitudinalpositions, as seen in longitudinal vertical planes of the improvedsurface effect ship, of forward water contacting portions of a gascushion forward seal member by at least twenty percent of a waterlinelength of the enhanced surface effect ship.

[0018] Yet still another related object of the invention is that watercontacting portions of said port and starboard bow members extend, asseen when the improved surface effect ship is moving forward at highspeed in a calm sea at a bow up trim angle of one and one-half degrees,forward of an average of longitudinal positions, as seen in longitudinalvertical planes of the improved surface effect ship, of forward watercontacting portions of a gas cushion forward seal member by at leasttwenty-five percent of a waterline length of the improved surface effectship.

[0019] Another object of the invention is that forward water contactingportions of said port and starboard bow members can further compriseartificially pressurized gas cushion portions disposed in theirundersides.

[0020] A directly related object of the invention is that theartificially pressurized gas cushion portions disposed in the undersidesof the port and starboard bow members extend, as seen when the improvedsurface effect ship is moving forward at high speed in a calm sea at abow up trim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of forward water contacting portions of agas cushion forward seal member.

[0021] Yet another related object of the invention is that theartificially pressurized gas cushion portions disposed in the undersidesof the port and starboard bow members extend, as seen when the improvedsurface effect ship is moving forward at high speed in a calm sea at abow up trim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of forward water contacting portions of agas cushion forward seal member by at least five percent of a waterlinelength of the improved surface effect ship.

[0022] A further related object of the invention is that theartificially pressurized gas cushion portions disposed in the undersidesof the port and starboard bow members extend, as seen when the improvedsurface effect ship is moving forward at high speed in a calm sea at abow up trim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of forward water contacting portions of agas cushion forward seal member by at least ten percent of a waterlinelength of the improved surface effect ship.

[0023] Still another object of the invention is that the gas cushionportions disposed in the undersides of the port and starboard bowmembers diverge either side of vertical sidehull longitudinal planesgoing aft from their forward portions.

[0024] A directly related object of the invention is that the verticallongitudinal planes are vertical longitudinal centerline planes of theport and starboard sidehulls.

[0025] A further object of the invention is that water contactingportions of gas cushion forward seal member(s) disposed between the portand starboard sidehulls extends over less than twenty percent of anoverall width of the improved surface effect ship proximal the gascushion forward seal member(s).

[0026] A related object of the invention is that water contactingportions of said gas cushion forward seal member(s) disposed between theport and starboard bow members extends over less than twenty-fivepercent of an overall width of the improved surface effect ship proximalthe gas cushion forward seal member(s).

[0027] Yet another related object of the invention is that watercontacting portions of said gas cushion forward seal member(s) disposedbetween the port and starboard bow members extends over less than thirtypercent of an overall width of the improved surface effect ship proximalthe gas cushion seal member(s).

[0028] Still another related object of the invention is that watercontacting portions of a gas cushion forward seal member(s) disposedbetween the port and starboard bow members extends over less thanthirty-five percent of an overall width of the improved surface effectship proximal the gas cushion forward seal member(s).

[0029] Yet another related object of the invention is that watercontacting portions of said gas cushion forward seal member(s) disposedbetween the port and starboard bow members extends over less than fortypercent of an overall width of the improved surface effect ship proximalthe gas cushion forward seal member(s).

[0030] Another related object of the invention is that water contactingportions of said gas cushion forward seal member disposed between theport and starboard bow members extends over less than fifty percent ofan overall width of the improved surface effect ship proximal the gascushion forward seal member(s).

[0031] Another important object of the invention is that inboardportions of the port and starboard sidehulls are truncated over aportion of their length aft of their bow portions.

[0032] A related object of the invention is that truncated aft extendingportions of said port and starboard sidehulls extend downward from anupper portion of a gas cushion recess to thereby form, at leastpartially, fluid fences that at least partially separate portions of theartificially pressurized gas cushion(s).

[0033] A directly related object of the invention is that, when theimproved surface effect ship is moving forward at high speed in a calmsea at a one and one-half degree bow up trim angle, said fluid fences ofsaid port and starboard sidehulls are not in contact with a watersurface over a majority of their length.

[0034] A further object of the invention is that a gas cushion aft seal,as seen in a vertical transverse plane of the improved surface effectship, comprises at least two inverted-V shaped portions.

[0035] A further object of the invention is that the port and starboardbow members diverge either side of vertical sidehull longitudinal planesgoing aft from forward portions of their bows.

[0036] A directly related object of the invention is that the verticalsidehull longitudinal planes are vertical sidehull centerline planes ofthe port and starboard sidehulls.

[0037] A further object of the invention is that forward watercontacting portions of said port and starboard bow members divergeeither side of their water contacting bow portions such that theirmeasured inboard and outboard divergence either side of their watercontacting bow portions is numerically within fifty percent of eachother.

[0038] Yet a further object of the invention is that a center hull maybe disposed between the port and starboard sidehulls.

[0039] A directly related object of the invention is that said centerhull may be truncated over its aft portion.

[0040] A further object of the invention is that gas cushion forwardseals may be disposed between the center hull and sidehulls.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041]FIG. 1 presents an underside 3D perspective of a preferredembodiment of the instant invention improved surface effect ship.

[0042]FIG. 2 is an underside plan view of the improved surface effectship of FIG. 1.

[0043]FIG. 3 is a topside plan view of the improved surface effect shipof FIG. 1 with the main deck removed to show machinery arrangements.

[0044]FIG. 4 gives a bow view of the preferred embodiment of the instantinvention improved surface effect ship.

[0045]FIG. 5 is a stern view of the instant invention improved surfaceeffect ship.

[0046]FIG. 6 presents an external side view of the instant inventionimproved surface effect ship.

[0047]FIG. 7 is a cross-sectional view, as taken through line 7-7 ofFIG. 2, that shows a section of the improved surface effect ship forwardof the gas cushion(s).

[0048]FIG. 8 presents a cross-sectional view, as taken through line 8-8of FIG. 2. This shows fluid fences that at least partially separateportions of the gas cushion(s).

[0049]FIG. 9 gives a centerline cross-section, as taken through line 9-9of FIG. 2, that shows a transverse section of the gas cushion aft sealjust forward of a transom.

[0050]FIG. 10 presents a cross sectional view, as taken through line10-10 of FIG. 2, that shows a section of hull through a verticalcenterline plane of the hull. Note that the discharge of the gaspressurizing blower is discharged aft and downward here to aid insealing gas cushion pressurized gas from escaping forward.

[0051]FIG. 11 is a cross sectional view, as taken through line 11-11 ofFIG. 2, that shows part of an air cushion recess in way of a sidehull'svertical centerline plane.

[0052]FIG. 12 presents an enlarged partial cross section, as takenthrough line 12-12 of FIG. 2 that shows how the blower discharge gas isaccelerated to thereby increase its dynamic pressure component. Note howthe waterline is depressed by the high energy of the gas discharginginto the gas cushion.

[0053]FIG. 13 presents a 3 dimensional look at a typical blower as itwould be discharging through an aft portion of a gas cushion forward gasseal member. Note how the gas has been accelerated to increase itsdynamic pressure component by necking down the discharge.

[0054]FIG. 4 gives a slight variation of the instant invention where acenter bow member has been installed between sidehulls. There are twoforward gas cushion seal members here. One is between each of thesidehull bows and the center bow.

[0055]FIG. 15 presents a bow view of the instant invention improvedsurface effect ship of claim 14.

[0056]FIG. 16 is a cross section, as taken through line 16-16 of FIG.14, that shows the blower discharges disposed in the forward gas cushionseals either side of the center bow member.

[0057]FIG. 12 gives another half-breadth cross section, as taken throughline 12-12 of FIG. 2, that illustrates a typical midship section. Notethe fluid fence that is vertically oriented here.

DETAILED DESCRIPTION

[0058]FIG. 1 presents an underside 3D perspective of the enhancedsurface effect ship 37 to the instant invention. Items to note areforward extending port bow member 49 and starboard bow 50. These bowmembers extend forward of a gas cushion forward seal member 38. In thiscase the gas cushion forward seal member 38 has the preferred inverted-Vshape. The inverted-V shape provides good rough sea ride qualities andalso presents a shape that concentrates the water coming off of the bows49, 50 to most effectively create a gas sealing effect. Artificiallypressurized gas is supplied to the gas cushion through gas dischargeopenings in the aft end of the gas cushion forward seal member 38 inthis preferred embodiment of the invention. Other means of supplyingpressurized gas to the gas cushion 48 can be employed and are consideredto be within the scope of the instant invention.

[0059] The pressurized gas is retained in the gas cushion 48 bysidehulls 42, bow members 49, 50, gas cushion forwrad seal member 38,gas cushion recess top 51, stem seal 44 and, of course, the watersurface. A set of fluid fences 41 are used here to restrict movement offluids from one portion of the gas cushion 48 to another. It isdesirable that these fluid fences 41 do not make water contact duringhigh speed operation in order to reduce wetted area frictionalresistance. Thrust is provided by propulsors 31. Some optional propulsorwater inlets 40 are shown here for illustrative purposes.

[0060]FIG. 2 gives a bottom plan view of the instant invention improvedsurface effect ship 37. Items shown are similar to those given in FIG. 1with the addition of gas flow arrows 47 that have been added. It showspart of the gas cushion forward seal member 38 disposed between the portand starboard bow members. Note how far the water contacting portions abow member 49 extends forward of the water contacting portion of the gascushion forward seal 38. This is an important consideration to theinstant invention enhanced surface effect ship 37 since it: 1) Providespitch stability forward of the gas cushion forward seal and 2) Allowsthe sidehulls to develop at least near full width where the gas cushionforward seal is located. Some definitions of the desired ranges ofextension of water contacting portions of the bow members forward of thewater contacting portions of the gas cushion forward seal are given in apreceding section titled SUMMARY OF THE INVENTION.

[0061]FIG. 3 presents a topside plan view with the primary deck portionremoved for illustrative purposes. This shows typical installation ofsome of the critical machinery elements. Included are propulsor driveshafts 35 and propulsor engines 33. A typical blower 32 is driven byblower drive engine 34.

[0062]FIG. 4 presents a bow view of the instant invention improvedsurface effect ship 37. Some items shown include a vertical centerlineplane 45 and sidehull vertical centerline planes 46 of the vessel. It isimportant to note the width of the lower water contacting portion of thegas cushion forward seal 38. It is about 25 percent of the total widthof the instant invention improved surface effect ship 37 proximal thegas cushion forward seal 38 here which is in a desired range. Somedefinitions of the desired limits on percentage of gas cushion forwardseal 38 width for the instant invention improved surface effect ship aregiven in a preceding section titled SUMMARY OF THE INVENTION. Thepercentage of total vessel width of the moveable bow seal of a genericSES is more like 80 percent. The very wide moveable bow seal of thegeneric SES makes for an effect like pushing a barn door sideways overthe surface of the water. While not a problem in calm water, the barndoor effect of the generic SES's moveable bow seal results in tremendousincreases in resistance and a severe degradation in ride quality as seastate increases. This is one of the major shortcomings that the instantinvention improved surface effect ship avoids since its gas cushionforward seal 38 is much narrower and also is primarily above a calm seasurface. Note that the waterline 30 between the sidehull bows 49, 50here are raised as formed by the wave action originating from theinboard sides of the sidehull bows 49, 50. This aids in the sealing ofthe pressurized gas inside of the gas cushion at of the gas cushionforward seal 38.

[0063]FIG. 5 shows a stern view that illustrates preferred locations ofpropulsors 31. Note the relatively flat shape of the gas cushion aftseal 44 which is the preferred design for low drag and good gas sealing.

[0064]FIG. 6 presents a vertical plane cross section, as taken throughline 6-6 of FIG. 2, that shows the shape and structure of the instantinvention improved surface effect ship 37 near and aft portion of thegas cushion forward seal 38. Note that this shows location of the blowerdischarge opening 39 just upstream of the gas cushion. The waterlines 30shown here give an idea of the sealing effect of the water below the gascushion forward seal 38. The waterlines 30 also show the desired levelof the water below the gas cushions 48 here.

[0065]FIG. 7 is a cross section, as taken through line 7-7 of FIG. 2,that shows shape of sidehull bows 49, 50 forward of the gas cushions.

[0066]FIG. 8 presents a typical midship cross section, as taken throughline 8-8 of FIG. 2, that shows a full span gas cushion that extendsbetween the sidehulls 42. Note that the waterline 30 below the gascushion 48 does not touch the fluid fences 41 in this depiction that isfor operation in a calm sea.

[0067]FIG. 9 gives a vertical plane cross section, as taken through line9-9 of FIG. 2, that shows a preferred shape of the gas cushion sternseal 44 which is near flat at this just forward of the transom section.Propulsor drive shafts 35 as intersected are shown here.

[0068]FIG. 10 presents a centerline plane cross sectional view, as takenthrough line 10-10 of FIG. 2 that shows a powered blower 32 driven by ablower motor 34. The discharge of the blower is at the aft end of thegas cushion forward seal 38 here. This approach allows the gas dischargethrough blower discharge opening 39 to help seal gas from leaking fromthe pressurized gas cushion 48. gives a profile view of the instantinvention enhanced surface effect ship 37.

[0069] In order to make definitions clear, it is stated here that theclaims are drawn based on the instant invention improved surface effectship 37 running forward at high speed in calm seas at a bow up trimangle of one and one-half degrees with the gas cushion(s) pressurized.High speed is defined as 15 knots or greater.

[0070]FIG. 11 gives a view taken through a vertical sidehull plane, astaken through line 11-11 of FIG. 2, that shows the preferred shape ofthe gas cushion 48 as it extends from forward in a sidehull bow 49 aftto a gas cushion aft seal 44.

[0071]FIG. 12 presents a partial cross section, as taken through line12-12 of FIG. 2, that shows how the gas discharge from a powered blower32 can aid in the sealing of the gas cushion 48. Note that the highvelocity of the gas discharge from the blower discharge opening 39actually depresses the incoming water as is shown by the depression ofthe waterline 30 aft of the gas discharge into the gas cushion 48.

[0072]FIG. 13 is a 3D illustration of a blower system to the preferredembodiment of the instant invention improved surface effect ship. Notethe converging design of the discharge 39 which adds to acceleration ofthe gas. It is to be noted that normal velocity of the gas dischargefrom a blower used in these craft would be about 5,000 feet per minute.By have the converging or nozzle effect, the gas is accelerated to about25,000 feet per minute (about half of the speed of sound at theseconditions). This increases dynamic pressure in the discharge gas byabout 25 times to bring it up to gas cushion pressure so that aneffective forward gas seal can be realized. For purposes of thisapplication, discharge velocities of at least 15,000, 20,000, 25,000, or30,000 feet per minute are considered feasible with state of the artblower equipment.

[0073] It is also to be realized also that, while the use of blowerdischarge gas to help seal the forward end of the gas cushion is thepreferred embodiment of the instant invention, it may not be necessaryto have the blower discharge as part of the gas cushion forward seal.This is the case if the waves coming from the bows create enough of abarrier to prevent pressurized gas from leaking forward past the gascushion forward seal(s) at unacceptably high rates.

[0074]FIG. 14 presents a simple variation, in a 3D undersideperspective, of the instant invention improved surface effect ship. Inthis instance there is a center bow member 52 and two partial sidehullbows 49, 50. There are two gas cushion forward seal members 38 hereextend between the sidehulls 49, 50 and the center bow member 52. Therewould, in the preferred embodiment here, be blowers discharging throughboth forward seal members 38. Note that the optional gas fences havebeen eliminated here. While desirable, it not necessary to incorporatethe gas fences in any of the instant invention improved surface effectships.

[0075]FIG. 15 presents a bow view of the instant invention improvedsurface effect ship 37 shown in FIG. 14. Note the two gas cushionforward seals 38 here.

[0076]FIG. 16 is a cross section, as taken through line 16-16 of FIG.14, that shows the hull shape in way of an aft end of the gas cushionforward seals 38. Note the blower gas flow discharges 39 here.

[0077] While the invention has been described in connection with apreferred and several alternative embodiments, it will be understoodthat there is no intention to thereby limit the invention. On thecontrary, there is intended to be covered all alternatives,modifications, and equivalents as may be included within the spirit andscope of the invention as defined by the appended claims, which are thesole definition of the invention.

What I claim is:
 1. In an improved surface effect ship wherein saidimproved surface effect ship includes port and starboard sidehulls andis supported upon a water surface in part by at least one artificiallypressurized gas cushion, the improvement comprising: a port and astarboard bow member wherein water contacting portions of said port andstarboard bow members extend, as seen when the improved surface effectship is moving forward at high speed in a calm sea at a bow up trimangle of one and one-half degrees, forward of an average of longitudinalpositions, as seen in longitudinal vertical planes of the improvedsurface effect ship, of forward water contacting portions of a gascushion forward seal member by at least five percent of a waterlinelength of the improved surface effect ship and wherein said gas cushionforward seal member is disposed, at least in part, between the port andstarboard bow members.
 2. The improved surface effect ship of claim 1wherein the gas cushion forward seal member is angled over a majority ofits width as seen in a vertical transverse plane of the improved surfaceeffect ship taken proximal an aft lower end of the gas cushion forwardseal member.
 3. The improved surface effect ship of claim 1 wherein thegas cushion forward seal member is at least in part of an inverted-Vshape as seen in a vertical transverse plane of the improved surfaceeffect ship taken proximal an aft lower end of the gas cushion forwardseal member.
 4. The improved surface effect ship of claim 1 whereinwater contacting portions of said port and starboard bow members extend,as seen when the improved surface effect ship is moving forward at highspeed in a calm sea at a bow up trim angle of one and one-half degrees,forward of an average of longitudinal positions, as seen in longitudinalvertical planes of the improved surface effect ship, of water contactingportions of the gas cushion forward seal member by at least ten percentof a waterline length of the improved surface effect ship.
 5. Theimproved surface effect ship of claim 1 wherein water contactingportions of said port and starboard bow members extend, as seen when theimproved surface effect ship is moving forward at high speed in a calmsea at a bow up trim angle of one and one-half degrees, forward of anaverage of longitudinal positions, as seen in longitudinal verticalplanes of the improved surface effect ship, of water contacting portionsof the gas cushion forward seal member by at least fifteen percent of awaterline length of the improved surface effect ship.
 6. The improvedsurface effect ship of claim 1 wherein water contacting portions of saidport and starboard bow members extend, as seen when the improved surfaceeffect ship is moving forward at high speed in a calm sea at a bow uptrim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of water contacting portions of the gascushion forward seal member by at least twenty percent of a waterlinelength of the improved surface effect ship.
 7. The improved surfaceeffect ship of claim 1 wherein water contacting portions of said portand starboard bow members extend, as seen when the improved surfaceeffect ship is moving forward at high speed in a calm sea at a bow uptrim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of forward water contacting portions ofthe gas cushion forward seal member by at least twenty-five percent of awaterline length of the improved surface effect ship.
 8. The improvedsurface effect ship of claim 1 wherein forward water contacting portionsof said port and starboard bow members further comprise artificiallypressurized gas cushion portions disposed in their undersides.
 9. Theimproved surface effect ship of claim 9 wherein the artificiallypressurized gas cushion portions disposed in the undersides of the portand starboard bow members extend, as seen when the improved surfaceeffect ship is moving forward at high speed in a calm sea at a bow uptrim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of forward water contacting portions ofthe gas cushion forward seal member.
 10. The improved surface effectship of claim 9 wherein the artificially pressurized gas cushionportions disposed in the undersides of the port and starboard bowmembers extend, as seen when the improved surface effect ship is movingforward at high speed in a calm sea at a bow up trim angle of one andone-half degrees, forward of an average of longitudinal positions, asseen in longitudinal vertical planes of the improved surface effectship, of forward water contacting portions of the gas cushion forwardseal member by at least five percent of a waterline length of theimproved surface effect ship.
 11. The improved surface effect ship ofclaim 9 wherein the artificially pressurized gas cushion portionsdisposed in the undersides of the port and starboard bow members extend,as seen when the improved surface effect ship is moving forward at highspeed in a calm sea at a bow up trim angle of one and one-half degrees,forward of an average of longitudinal positions, as seen in longitudinalvertical planes of the enhanced surface effect ship, of forward watercontacting portions of the gas cushion forward seal member by at leastten percent of a waterline length of the improved surface effect ship.12. The improved surface effect ship of claim 9 wherein the gas cushionportions disposed in the undersides of the port and starboard bowmembers diverge either side of vertical sidehull longitudinal planesgoing aft from their forward portions.
 13. The improved surface effectship of claim 13 wherein said vertical longitudinal planes are verticallongitudinal centerline planes of the port and starboard sidehulls. 14.The improved surface effect ship of claim 1 wherein said gas cushionforward seal member disposed between the port and starboard sidehullsextends over less than twenty percent of an overall width of theimproved surface effect ship proximal an aft portion of the gas cushionforward seal member.
 15. The improved surface effect ship of claim 1wherein the gas cushion forward seal member is less than twenty percentof a width of the improved surface effect ship as seen in a verticaltransverse plane of the improved surface effect ship taken proximal anaft end of the gas cushion forward seal member.
 16. The improved surfaceeffect ship of claim 1 wherein said gas cushion forward seal memberdisposed between the port and starboard bow members extends over lessthan twenty-five percent of an overall width of the improved surfaceeffect ship proximal said gas cushion forward seal member.
 17. Theimproved surface effect ship of claim 1 wherein said gas cushion forwardseal member disposed between the port and starboard bow members extendsover less than thirty percent of an overall width of the improvedsurface effect ship proximal an aft portion of the gas cushion forwardseal member.
 18. The improved surface effect ship of claim 1 whereinsaid gas cushion forward seal member disposed between the port andstarboard bow members extends over less than thirty-five percent of anoverall width of the improved surface effect ship proximal an aftportion of the gas cushion forward seal member.
 19. The improved surfaceeffect ship of claim 1 wherein said gas cushion forward seal memberdisposed between the port and starboard bow members extends over lessthan forty percent of an overall width of the improved surface effectship proximal an aft portion of the gas cushion forward seal member. 20.The improved surface effect ship of claim 1 wherein said gas cushionforward seal member disposed between the port and starboard bow membersextends over less than fifty percent of an overall width of the improvedsurface effect ship proximal an aft portion of the gas cushion forwardseal member.
 21. The improved surface effect ship of claim 1 whereininboard portions of the port and starboard sidehulls are at leastpartially truncated aft of their bow portions.
 22. The improved surfaceeffect ship of claim 1 wherein longitudinally oriented fluid fencesextend downward from upper surfaces of the gas cushion recess to therebyrestrict fluid flow in the gas cushion.
 23. The improved surface effectship of claim 22 wherein, when the improved surface effect ship ismoving forward at high speed in a calm sea at a one and one-half degreebow up trim angle, said fluid fences are not in contact with a watersurface over a majority of their length.
 24. The improved surface effectship of claim 1 wherein the port and starboard bow members divergeeither side of vertical sidehull longitudinal planes going aft fromforward portions of their bows.
 25. The improved surface effect ship ofclaim 24 wherein said vertical sidehull longitudinal planes are verticalsidehull centerline planes of the port and starboard sidehulls.
 26. Theimproved surface effect ship of claim 1 wherein a gas cushion aft sealmember, as seen in a vertical transverse plane of the improved surfaceeffect ship, comprises at least two inverted-V shaped portions.
 27. Theimproved surface effect ship of claim 1 wherein a gas cushion aft sealmember, as seen in a vertical transverse plane of the improved surfaceeffect ship, is angled to horizontal over a majority of its width. 28.The improved surface effect ship of claim 1 wherein pressurized gas isdischarged into the gas cushion proximal an aft end of a gas cushionforward seal.
 29. The improved surface effect ship of claim 28 whereinpressurized gas is discharged into the gas cushion proximal an aft endof a gas cushion forward seal at an average velocity of more than 30,000feet per minute.
 30. The improved surface effect ship of claim 28wherein pressurized gas is discharged into the gas cushion proximal anaft end of a gas cushion forward seal at an average velocity of morethan 25,000 feet per minute.
 31. The improved surface effect ship ofclaim 28 wherein pressurized gas is discharged into the gas cushionproximal an aft end of a gas cushion forward seal at an average velocityof more than 20,000 feet per minute.
 32. The improved surface effectship of claim 28 wherein pressurized gas is discharged into the gascushion proximal an aft end of a gas cushion forward seal at an averagevelocity of more than 15,000 feet per minute.
 33. The improved surfaceeffect ship of claim 1 wherein there is a third bow member disposedinboard of port and starboard bow members.
 34. The improved surfaceeffect ship of claim 1 wherein there is a third bow member and whereingas cushion forward seal members are disposed between port and starboardbow members and the third bow member.
 35. In an improved surface effectship wherein said improved surface effect ship includes port andstarboard sidehulls and is supported upon a water surface in part by atleast one artificially pressurized gas cushion, the improvementcomprising: a port and a starboard bow member with a gas cushion forwardseal member disposed between said port and starboard bow members andwherein pressurized gas is discharged rearward into the gas cushion fromproximal an aft lower portion of the gas cushion forward seal member tothereby create a pressurized gas seal and wherein said gas cushionforward seal member, as seen in a vertical transverse plane of theimproved surface effect ship located proximal an aft lower portion ofthe gas cushion forward seal member, is no more than fifty percent of awidth of the improved surface effect ship.
 36. The improved surfaceeffect ship of claim 35 wherein said gas cushion forward seal member, asseen in a vertical transverse plane of the improved surface effect shiplocated proximal an aft lower portion of the gas cushion forward sealmember, is no more than forty percent of a width of the improved surfaceeffect ship.
 37. The improved surface effect ship of claim 35 whereinsaid gas cushion forward seal member, as seen in a vertical transverseplane of the improved surface effect ship located proximal an aft lowerportion of the gas cushion forward seal member, is no more thanthirty-five percent of a width of the improved surface effect ship. 38.The improved surface effect ship of claim 35 wherein said gas cushionforward seal member, as seen in a vertical transverse plane of theimproved surface effect ship located proximal an aft lower portion ofthe gas cushion forward seal member, is no more than thirty percent of awidth of the improved surface effect ship.
 39. The improved surfaceeffect ship of claim 35 wherein said gas cushion forward seal member, asseen in a vertical transverse plane of the improved surface effect shiplocated proximal an aft lower portion of the gas cushion forward sealmember, is no more than twenty-five percent of a width of the improvedsurface effect ship.
 40. The improved surface effect ship of claim 35wherein said gas cushion forward seal member, as seen in a verticaltransverse plane of the improved surface effect ship located proximal anaft lower portion of the gas cushion forward seal member, is no morethan twenty percent of a width of the improved surface effect ship. 41.The improved surface effect ship of claim 35 wherein water contactingportions of said port and starboard bow members extend, as seen when theimproved surface effect ship is moving forward at high speed in a calmsea at a bow up trim angle of one and one-half degrees, forward of anaverage of longitudinal positions, as seen in longitudinal verticalplanes of the improved surface effect ship, of water contacting portionsof the gas cushion forward seal member by at least five percent of awaterline length of the improved surface effect ship.
 42. The improvedsurface effect ship of claim 35 wherein water contacting portions ofsaid port and starboard bow members extend, as seen when the improvedsurface effect ship is moving forward at high speed in a calm sea at abow up trim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of water contacting portions of the gascushion forward seal member by at least ten percent of a waterlinelength of the improved surface effect ship.
 43. The improved surfaceeffect ship of claim 35 wherein water contacting portions of said portand starboard bow members extend, as seen when the improved surfaceeffect ship is moving forward at high speed in a calm sea at a bow uptrim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of water contacting portions of the gascushion forward seal member by at least fifteen percent of a waterlinelength of the improved surface effect ship.
 44. The improved surfaceeffect ship of claim 35 wherein water contacting portions of said portand starboard bow members extend, as seen when the improved surfaceeffect ship is moving forward at high speed in a calm sea at a bow uptrim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of water contacting portions of the gascushion forward seal member by at least twenty percent of a waterlinelength of the improved surface effect ship.
 45. The improved surfaceeffect ship of claim 35 wherein water contacting portions of said portand starboard bow members extend, as seen when the improved surfaceeffect ship is moving forward at high speed in a calm sea at a bow uptrim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of water contacting portions of the gascushion forward seal member by at least twenty-five percent of awaterline length of the improved surface effect ship.
 46. The improvedsurface effect ship of claim 35 wherein forward water contactingportions of said port and starboard bow members further compriseartificially pressurized gas cushion portions disposed in theirundersides.
 47. The improved surface effect ship of claim 46 wherein theartificially pressurized gas cushion portions disposed in the undersidesof the port and starboard bow members extend, as seen when the improvedsurface effect ship is moving forward at high speed in a calm sea at abow up trim angle of one and one-half degrees, forward of an average oflongitudinal positions, as seen in longitudinal vertical planes of theimproved surface effect ship, of forward water contacting portions ofthe gas cushion forward seal member by at least five percent of awaterline length of the improved surface effect ship.
 48. The improvedsurface effect ship of claim 46 wherein the artificially pressurized gascushion portions disposed in the undersides of the port and starboardbow members extend, as seen when the improved surface effect ship ismoving forward at high speed in a calm sea at a bow up trim angle of oneand one-half degrees, forward of an average of longitudinal positions,as seen in longitudinal vertical planes of the improved surface effectship, of forward water contacting portions of the gas cushion forwardseal member by at least ten percent of a waterline length of theimproved surface effect ship.
 49. The improved surface effect ship ofclaim 46 wherein the gas cushion portions disposed in the undersides ofthe port and starboard bow members diverge either side of verticalsidehull longitudinal planes going aft from their forward portions. 50.The improved surface effect ship of claim 48 wherein said verticallongitudinal planes are vertical longitudinal centerline planes of theport and starboard sidehulls.
 51. The improved surface effect ship ofclaim 35 wherein inboard portions of the port and starboard sidehullsare at least partially truncated aft of their bow portions.
 52. Theimproved surface effect ship of claim 35 wherein longitudinally orientedfluid fences extend downward from upper surfaces of the gas cushionrecess to thereby restrict fluid flow in the gas cushion.
 53. Theimproved surface effect ship of claim 52 wherein, when the improvedsurface effect ship is moving forward at high speed in a calm sea at aone and one-half degree bow up trim angle, said fluid fences are not incontact with a water surface over a majority of their length.
 54. Theimproved surface effect ship of claim 35 wherein a gas cushion aft sealmember, as seen in a vertical transverse plane of the improved surfaceeffect ship, comprises at least two inverted-V shaped portions.
 55. Theimproved surface effect ship of claim 35 wherein a gas cushion aft sealmember, as seen in a vertical transverse plane of the improved surfaceeffect ship, is angled to horizontal over a majority of its width. 56.The improved surface effect ship of claim 35 wherein pressurized gas isdischarged into the gas cushion proximal an aft end of a gas cushionforward seal at an average velocity of more than 15,000 feet per minute.57. The improved surface effect ship of claim 35 wherein pressurized gasis discharged into the gas cushion proximal an aft end of a gas cushionforward seal at an average velocity of more than 20,000 feet per minute.58. The improved surface effect ship of claim 35 wherein pressurized gasis discharged into the gas cushion proximal an aft end of a gas cushionforward seal at an average velocity of more than 25,000 feet per minute.59. The improved surface effect ship of claim 35 wherein pressurized gasis discharged into the gas cushion proximal an aft end of a gas cushionforward seal at an average velocity of more than 30,000 feet per minute.60. The improved surface effect ship of claim 35 wherein there is athird bow member disposed inboard of port and starboard bow members. 61.The improved surface effect ship of claim 35 wherein there is a thirdbow member and wherein gas cushion forward seal members are disposedbetween port and starboard bow members and the third bow member.
 62. Inan improved surface effect ship wherein said improved surface effectship includes port and starboard sidehulls and is supported upon a watersurface in part by at least one artificially pressurized gas cushion,the improvement comprising: a third hull member disposed at least inpart between the said port and starboard sidehull bows wherein gascushion forward seal members are disposed, at least in part, between theport sidehull bow and the third hull member and between the starboardsidehull bow and the third hull member.
 63. The improved surface effectship of claim 62 wherein pressurized gas is discharged into the gascushion from proximal aft ends of the gas cushion forward seal members.64. The improved surface effect ship of claim 63 wherein the pressurizedgas discharged into the gas cushion from proximal aft ends of the gascushion forward seal members is discharged into the gas cushion ataverage velocities of more than 15,000 feet per minute.
 65. The improvedsurface effect ship of claim 63 wherein the pressurized gas dischargedinto the gas cushion from proximal aft ends of the gas cushion forwardseal members is discharged into the gas cushion at average velocities ofmore than 20,000 feet per minute.
 66. The improved surface effect shipof claim 63 wherein the pressurized gas discharged into the gas cushionfrom proximal aft ends of the gas cushion forward seal members isdischarged into the gas cushion at average velocities of more than25,000 feet per minute.
 67. The improved surface effect ship of claim 62wherein the gas cushion forward seals, as seen in vertical transverseplanes of the improved surface effect ship, are angled to horizontalover a majority of their width.
 68. The improved surface effect ship ofclaim 62 wherein inboard portions of the port and starboard sidehullsare at least partially truncated aft of their bow portions.
 69. Theimproved surface effect ship of claim 62 wherein longitudinally orientedfluid fences extend downward from upper surfaces of the gas cushionrecess to thereby restrict fluid flow in the gas cushion.
 70. Theimproved surface effect ship of claim 62 wherein forward watercontacting portions of said port and starboard bow members furthercomprise artificially pressurized gas cushion portions disposed in theirundersides.